It cannot be harmed except with blessed or silver objects, magic, or artifact weapons with a damage bonus. Orcus Town is the only place where shades appear. If you've gotten this far without an alternative, you can use the Bell of Opening as a silver weapon against them. Unarmed gloveless combat with a silver ring equipped can also work, as can unarmed combat with blessed gloves (although this is very slow.)

Shades can also move freely through solid rock, and can see invisible creatures.